Photovoltaic systems include photovoltaic cell modules, a stand for mounting the photovoltaic cell modules, and electric components such as an inverter for obtaining an output from the photovoltaic cell modules. Photovoltaic power generation system which is composed of a number of photovoltaic systems and has an output in the order of 1 MW or more is called mega solar systems. In the mega solar systems, a number of photovoltaic systems are required to be constructed with low cost and high quality. Accordingly, a photovoltaic system manufactured with low cost is proposed (for example, see Japanese Unexamined Patent Application Publication No. 2007-251001).